/*
 * @Author: long-xinyu2 2192763423@qq.com
 * @Date: 2025-03-11 18:47:55
 * @LastEditors: long-xinyu2 2192763423@qq.com
 * @LastEditTime: 2025-03-25 18:46:43
 * @FilePath: \algorithm\algorithm-training\2025_3_11.cpp
 * @Description: 这是默认设置,请设置`customMade`, 打开koroFileHeader查看配置 进行设置: https://github.com/OBKoro1/koro1FileHeader/wiki/%E9%85%8D%E7%BD%AE
 */
#include<iostream>
#include<cstring>
#include<vector>
#include<map>
#include<cstdio>
#include<algorithm>
#include<string>
#include<string.h>
#include<queue>
#include<math.h>
#include<set>
#include<functional>
using namespace std;
using ull = unsigned long long;
#define int long long
//using i128 = __int128_t;
inline int inc(int x, int v, int mod) { x += v;return x >= mod ? x - mod : x; }//代替取模+
#define endl '\n'
typedef long long LL;
typedef unsigned long long ULL;
typedef pair<int, int> PII;

const int N = 2e3 + 10, M = 1e5 + 10;

inline int read()
{
    int x = 0, f = 1;
    char ch = getchar();
    while (ch < '0' || ch > '9')
    {
        if (ch == '-')
            f = -1;
        ch = getchar();
    }
    while (ch >= '0' && ch <= '9')
        x = x * 10 + ch - '0', ch = getchar();
    return x * f;
}

bool cmp(pair<int,int> &a,pair<int,int> &b)
{
    if(a.first != b.first) return a.first < b.first;
    else return a.second > b.second;
}


void solve()
{
    int n;
    cin >> n;
    vector<pair<int,int>> vec;
    map<pair<int,int>,int> mp;
    for(int i = 1; i <= n; i ++)
    {
        int l,r;
        cin >> l >> r;
        vec.push_back({l,r});
        mp[{l,r}] = i;
    }
    sort(vec.begin(),vec.end(),cmp);
    int r = 0;
    vector<pair<int,int>> ans;
    for(int i = 0; i < vec.size(); i ++)
    {
        if(vec[i].second <= r) continue;
        else 
        {
            r = vec[i].second;
            ans.push_back(vec[i]);
        }
    }
    cout << ans.size() << endl;
    for(int i = 0; i < ans.size(); i ++)
    {
        cout << mp[ans[i]] << ' ';
    }
    cout << endl;
}
signed main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    int tt;
    cin >> tt;
    //tt = 1;
    while (tt--)
    {
        solve();
    }
}